1. Field of the Invention
The invention relates to a safety and arming unit including a safe separation distance device, which acts as a function of an incident flow and temperature utilized for the fuze of a projectile
2. Discussion of the Prior Art
A safety and arming unit of this type is known from DE 31 26 289 C for a projectile in order to ensure its second safety criterion, the safe separation distance following the launch-dependent first safety criterion. There, ram-air pressure channels, into which an unlocking element which is deformed as a function of temperature projects, run approximately parallel to the axis through the fuze between inlet openings in the end surface and outlet openings in the truncated-conical coating surface of the fuze. Once this unlocking element has been heated sufficiently intensively by the ram-air flow resulting from sufficiently long free flight, it changes its geometric shape and in consequence unlocks the second arming element, which is spring-loaded, in order to enable the projectile fuze, which will respond later, for example on striking a target.
Mechanical unlocking such as this is, however, functionally critical and generally susceptible to defects, particularly after long depot storage times. Furthermore, the compressed incident flow emerging from the fuze casing surfaces adversely affects the ballistic behaviour of the projectile. Sufficiently rapid, strong ram-air pressure heating in flow channels such as this does not occur at all, where possible, in a relatively slow projectile such as a guided missile. When a projectile such as this is operated at low altitude and in particular in a sandy, dusty environment or one in which cold moisture results in a risk of icing, there is even a risk of the flow channels becoming blocked and therefore in failure of the second arming criterion, as a result of which the projectile becomes a misfire.
Against this background, the invention is based on the technical problem of designing a safety and arming unit of this generic type for reliable operation particularly and additionally in the case of relatively slow projectiles and in critical environmental conditions, and also of providing the capability to intervene in the second arming criterion, in this context.